The development of shale reservoirs is important in ensuring China’s national energy security by achieving energy independence. Among the key technologies for shale oil production, CO₂ fracturing is an effective method that can not only enhance oil recovery but also promote large amounts of CO₂ storage, thereby supporting China’s goals of achieving a carbon peak and carbon neutrality. This research paper aims to study the impacts and prospective applications of CO₂ fracturing in shale reservoirs, using real exploitation parameters from the GYYP1 well in the Songliao Basin. By utilizing numerical simulation, the dynamics of CO₂ production are analyzed. Adsorption and diffusion are identified as pivotal mechanisms for CO₂ storage in shale reservoirs. After the analysis of the fracturing process, approximately 22.13% of CO₂ is found to be adsorbed, which decreases to 11.06% after ten years due to pressure decline. Diffusion increases the volume of CO₂ interacting with a greater extent of shale, thereby enhancing the adsorption mechanism. Over time, the diffusion process results in a remarkable increase of 26.02% in CO₂ adsorption, ensuring the long-term and stable storage of CO₂ within the shale reservoir. This investigation delves into the contribution of these two crucial mechanisms of CO₂ storage in shale reservoirs, ultimately predicting that, by 2030, approximately two million tons of CO₂ can be effectively stored in the Daqing Oilfield through CO₂ fracturing in shale oil reservoirs. Such an achievement will undoubtedly contribute to the sustainable development of the energy sector and foster the transformation and upgrading of China’s energy structure.